US5369634A - Transmission quality assessment arrangement - Google Patents

Transmission quality assessment arrangement Download PDF

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Publication number
US5369634A
US5369634A US07/699,968 US69996891A US5369634A US 5369634 A US5369634 A US 5369634A US 69996891 A US69996891 A US 69996891A US 5369634 A US5369634 A US 5369634A
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United States
Prior art keywords
cell
output
stream
count
input
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Expired - Fee Related
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US07/699,968
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English (en)
Inventor
Frank L. Denissen
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Alcatel Lucent NV
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Alcatel NV
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Assigned to ALCATEL N.V., A CORP OF NETHERLANDS reassignment ALCATEL N.V., A CORP OF NETHERLANDS ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DENISSEN, FRANK L.
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L43/00—Arrangements for monitoring or testing data switching networks
    • H04L43/50—Testing arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector

Definitions

  • the present invention relates to a transmission quality assessment arrangement for a communication switching system wherein a stream of cells of information is transmitted from an input to an output over a same communication path.
  • An object of the present invention is to provide a more effective transmission quality assessment arrangement which while using a limited amount of additional bandwidth nevertheless allows to assess the transmission quality with a relatively higher accuracy.
  • the object is achieved due to the fact that it includes :
  • a quality assessment circuit including a comparator (8) to compare the counted test cell position with the position indicated by the tag thereof and evaluation circuitry coupled to said comparator to derive from said comparison an indication of the cell transmission quality.
  • connections between the blocks are all represented by single wires although each of them may be constituted by a plurality of such wires.
  • the communication switching system 1 is for instance a digital swiching system of the type disclosed in the above mentioned European patent application No. 88900074.1
  • cells or packets of information belonging to a same communication are transmitted from any of a plurality of inputs to any of a plurality of outputs along a same virtual transmission path which has been determined previously by a path setup cell. Since in the following description only a single communication on a same path will be considered only one input terminal I and one output terminal 0 of this path in the switching system 1 are shown.
  • the transmission quality assessment arrangement TQA includes a cell input circuit CIC coupled to input terminal I, a cell output circuit COC coupled to output terminal 0 and a transmission quality assessment circuit QAC coupled to the cell output circuit COC.
  • the cell input circuit CIC comprises a cell input and multiplexer circuit 2, a cell input counter 3 and a test cell generator 4.
  • the input multiplexer circuit 2 has a normal cell input IN, a test cell input TI, an enable output F connected to the test cell generator 4 and an output which is coupled to the input terminal I of the switching system 1 via the counter 3 having an enable output G and a count output N both coupled to like named inputs of the test cell generator 4.
  • the output thereof is connected to the test cell input TI of the input and multiplexer circuit 2.
  • the enable output F is activated when the circuit 2 detects that there is a free cell position because no normal cell has been received, whilst the enable output G is activated when the counter 3 has counted a predetermined number of cells, say M.
  • the cell output circuit COC comprises a cell output counter 5, a cell output and demultiplexer circuit 6 and a test cell analyser 7.
  • the output terminal 0 of the switching system 1 is connected, via the cell output counter 5, to the input of the output and demultiplexer circuit G having a normal cell output OUT as well as a test cell output TO which is coupled to the like named input of the test cell analyzer 7 provided with a trigger output T and a number output E.
  • the latter outputs are coupled to like named inputs of the counter 5 and of the test quality assessment circuit QAC to which also a count output R of the counter 5 is connected.
  • the quality assessment circuit QAC comprises a comparator 8, an added cells accumulator 9, an added cells threshold circuit 10, a lost cells accumulator 11, a lost cells threshold circuit 12, and a modulo cell counter 13.
  • the circuits 9, 10, 11, 12 and 13 constitute evaluation circuitry.
  • the respective outputs R and E of the counter 5 and the test cell analyzer 7 are coupled to inputs of the comparator 8.
  • the latter has outputs A and L which are coupled to like named increment inputs of the accumulator 9 and 11 respectively, both these accumulators having an enable input T to which the enable output T of the analyzer 7 is linked.
  • the accumulators 9 and 11 have respective sum outputs Z+A and K+L which constitute respective output terminals QA and QL of the TQA and which are moreover coupled to like named inputs of the threshold circuits 10 and 12.
  • the latter also have a reset input S connected to an output of the counter 13 whose input R is connected to the count output R of counter 5.
  • Outputs AA and AL of the threshold circuits 10 and 12 constitute alarm output terminals of the TQA.
  • the above described transmission quality assessment arrangement TQA operates as follows when normal cells belonging to a same communication are applied to the input terminal IN.
  • Each of these cells has a header and a data field: the header contains information identifying the communication to which the cell belongs and a tag indicating that it is a normal cell, whilst the data field contains data.
  • the cell input and multiplexer circuit 2 derives therefrom that a normal cell is concerned and feeds the latter to the counter 3 which counts the cell and then applies it to the input terminal I of the switching system 1.
  • the counter 3 also provides at its count output N a number equal to the normal cell count plus 1 and applies it to the generator A.
  • this signal has no effect on the generator 4 as long as the enable inputs G and F thereof are not simultaneously activated.
  • the cell is transmitted to the output terminal 0 where it is counted by the counter 5 and then applied to the output terminal OUT via the cell output and demultiplexer circuit 6 after the latter has detected from the cell header that a normal cell is concerned.
  • the cell count provided at the output R of the counter 5 is applied to both the comparator 8 and the modulo counter 13 of the quality assessment circuit QAC which will be considered later.
  • the input and multiplexer circuit 2 detects the absence of a normal input cell and therefore a free cell position it activates its enable output F. However this has no effect as long as the counter 3 has not reached the cell count M. When this happens this counter 3 provides the cell count M+1 to the generator 4 and as a consequence the latter then generates a test cell similar to a normal communication cell i.e. with a header containing information relating to the communication to which the test cell belongs and an identification tag indicative of a test cell, and with a data field storing a position indicating tag constituted by the above cell count or cell position M+1.
  • test cell thus generated is applied to the test cell input TI of the input and multiplexer circuit 2 and is then transmitted via the counter 3 and the switching system 1 to the counter 5 as the (M+1)th cell of the communication i.e. of the resultant cell stream of normal and test cells.
  • the test cell is counted and the count value M+1 is applied to the inputs R of 8 and 13, the test cell being applied to the output and demultiplexer circuit G.
  • the analyzer 7 extracts the position indicating tag M+1 from the data field of the test cell and applies it to the count inputs E of the cell counter 5 and of the comparator 8.
  • the comparator 8 provides the difference value E-R which is zero or positive when the cell count R is equal to or smaller than the expected cell count M+1 provided at the output E, This happens when everything is normal or when cells have been lost from a communication respectively, the number of lost cells being equal to E-R.
  • the values Z+A and K+L are also applied to the threshold circuits 10 and 12 each of which activates the signal of its respective alarm output AA or AL when the value Z+A or K+L exceeds a respective threshold value.
  • each of the threshold circuits is reset when the modulo counter 13 has counted this predetermined total number and has accordingly activated its output S.
  • the generator circuit 4 also preferably includes a timer (not shown) which independently from the condition of the inputs G and F generates a test cell each time a predetermined time interval has elapsed and applies it to the multiplexer input TI having priority over the other input IN thereof. In this way one is sure that a minimum number of test cells will be transmitted.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
US07/699,968 1990-05-15 1991-05-14 Transmission quality assessment arrangement Expired - Fee Related US5369634A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP90201219A EP0456914B1 (en) 1990-05-15 1990-05-15 Transmission quality assessment arrangement
EP90201219.4 1990-05-15

Publications (1)

Publication Number Publication Date
US5369634A true US5369634A (en) 1994-11-29

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US07/699,968 Expired - Fee Related US5369634A (en) 1990-05-15 1991-05-14 Transmission quality assessment arrangement

Country Status (8)

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US (1) US5369634A (ja)
EP (1) EP0456914B1 (ja)
JP (1) JPH04230143A (ja)
KR (1) KR0155564B1 (ja)
AU (1) AU631066B2 (ja)
CA (1) CA2042516C (ja)
DE (1) DE69015165T2 (ja)
ES (1) ES2068324T3 (ja)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5477549A (en) * 1991-01-08 1995-12-19 Kabushiki Kaisha Toshiba Cell switch and cell switch network using dummy cells for simplified cell switch test in communication network
US5875177A (en) * 1991-09-12 1999-02-23 Fujitsu Limited Path test system for ATM switch
US5883665A (en) * 1997-09-26 1999-03-16 Lucent Technologies Inc. Testing system for simulating human faculties in the operation of video equipment
US6147998A (en) * 1997-08-26 2000-11-14 Visual Networks Technologies, Inc. Method and apparatus for performing in-service quality of service testing
US6584069B1 (en) * 1998-08-31 2003-06-24 Matsushita Electric Industrial Co., Ltd Packet filtering apparatus that applies a plurality of filtering conditions including different comparison criteria to a single packet
US20060236183A1 (en) * 2001-02-02 2006-10-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US7194661B1 (en) * 2002-12-23 2007-03-20 Intel Corporation Keep alive buffers (KABs)
US20070165472A1 (en) * 2001-02-02 2007-07-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2097350C (en) * 1992-08-17 1998-12-22 Shahrukh S. Merchant Asynchronous transfer mode (atm) transmission test cell generator
FR2701618B1 (fr) * 1993-02-16 1995-06-23 Tremel Jean Yves Procede de mesure de parametres de performance d'un reseau atm et dispositif de mise en oeuvre.
DE19934622A1 (de) * 1999-07-23 2001-01-25 Deutsche Telekom Ag Verfahren zur Prüfung und Fehlerdiagnose einer Standardfestverbindung in einem Telekommunikationsnetz sowie hierfür einsetzbare Vorrichtung

Citations (10)

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Publication number Priority date Publication date Assignee Title
US4494230A (en) * 1982-06-25 1985-01-15 At&T Bell Laboratories Fast packet switching system
US4561090A (en) * 1983-05-18 1985-12-24 At&T Bell Laboratories Integrated self-checking packet switch node
US4752929A (en) * 1985-03-26 1988-06-21 Siemens Aktiengesellschaft Method of operating a semiconductor memory with a capability of testing, and an evaluation circuit for performing the method
US5020055A (en) * 1989-06-23 1991-05-28 May Jr Carl J Multi-length packet format including fixed length information words
US5020052A (en) * 1986-12-19 1991-05-28 Alcatel N.V. Packet switching network
US5027343A (en) * 1989-04-21 1991-06-25 Northern Telecom Limited Remote test access system for ISDN testing
US5040171A (en) * 1989-01-24 1991-08-13 Kabushiki Kaisha Toshiba Call restricting method in packet switching network and network controller having call restricting function
US5042032A (en) * 1989-06-23 1991-08-20 At&T Bell Laboratories Packet route scheduling in a packet cross connect switch system for periodic and statistical packets
US5163057A (en) * 1989-04-18 1992-11-10 Wandel & Goltermann Gmbh & Co. Method of and circuit arrangement for determining a cell loss and/or a cell insertion during traversal of a cell oriented transmission device by cell structured signals
US5231598A (en) * 1991-09-30 1993-07-27 National Semiconductor Corporation Direct digital synthesis measurement signal skew tester

Patent Citations (10)

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US4494230A (en) * 1982-06-25 1985-01-15 At&T Bell Laboratories Fast packet switching system
US4561090A (en) * 1983-05-18 1985-12-24 At&T Bell Laboratories Integrated self-checking packet switch node
US4752929A (en) * 1985-03-26 1988-06-21 Siemens Aktiengesellschaft Method of operating a semiconductor memory with a capability of testing, and an evaluation circuit for performing the method
US5020052A (en) * 1986-12-19 1991-05-28 Alcatel N.V. Packet switching network
US5040171A (en) * 1989-01-24 1991-08-13 Kabushiki Kaisha Toshiba Call restricting method in packet switching network and network controller having call restricting function
US5163057A (en) * 1989-04-18 1992-11-10 Wandel & Goltermann Gmbh & Co. Method of and circuit arrangement for determining a cell loss and/or a cell insertion during traversal of a cell oriented transmission device by cell structured signals
US5027343A (en) * 1989-04-21 1991-06-25 Northern Telecom Limited Remote test access system for ISDN testing
US5020055A (en) * 1989-06-23 1991-05-28 May Jr Carl J Multi-length packet format including fixed length information words
US5042032A (en) * 1989-06-23 1991-08-20 At&T Bell Laboratories Packet route scheduling in a packet cross connect switch system for periodic and statistical packets
US5231598A (en) * 1991-09-30 1993-07-27 National Semiconductor Corporation Direct digital synthesis measurement signal skew tester

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W. Boghdady, "A Technique For Fault-Detection and . . . ", IEEE Int'l Conf. on Comm., Proceedings vol. 3, pp. 1011-1512, May 14-17, 1984.
W. Boghdady, A Technique For Fault Detection and . . . , IEEE Int l Conf. on Comm., Proceedings vol. 3, pp. 1011 1512, May 14 17, 1984. *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5477549A (en) * 1991-01-08 1995-12-19 Kabushiki Kaisha Toshiba Cell switch and cell switch network using dummy cells for simplified cell switch test in communication network
US5875177A (en) * 1991-09-12 1999-02-23 Fujitsu Limited Path test system for ATM switch
US6147998A (en) * 1997-08-26 2000-11-14 Visual Networks Technologies, Inc. Method and apparatus for performing in-service quality of service testing
US5883665A (en) * 1997-09-26 1999-03-16 Lucent Technologies Inc. Testing system for simulating human faculties in the operation of video equipment
US6584069B1 (en) * 1998-08-31 2003-06-24 Matsushita Electric Industrial Co., Ltd Packet filtering apparatus that applies a plurality of filtering conditions including different comparison criteria to a single packet
US7360127B2 (en) 2001-02-02 2008-04-15 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US20070165472A1 (en) * 2001-02-02 2007-07-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US20060236183A1 (en) * 2001-02-02 2006-10-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US7490275B2 (en) 2001-02-02 2009-02-10 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US20100251040A1 (en) * 2001-02-02 2010-09-30 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US8069378B2 (en) 2001-02-02 2011-11-29 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US8756469B2 (en) 2001-02-02 2014-06-17 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US8812919B2 (en) 2001-02-02 2014-08-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US8812918B2 (en) 2001-02-02 2014-08-19 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US9356743B2 (en) 2001-02-02 2016-05-31 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US10855413B2 (en) 2001-02-02 2020-12-01 Rambus Inc. Method and apparatus for evaluating and optimizing a signaling system
US7194661B1 (en) * 2002-12-23 2007-03-20 Intel Corporation Keep alive buffers (KABs)

Also Published As

Publication number Publication date
KR910021066A (ko) 1991-12-20
EP0456914B1 (en) 1994-12-14
DE69015165T2 (de) 1995-05-24
AU631066B2 (en) 1992-11-12
ES2068324T3 (es) 1995-04-16
KR0155564B1 (ko) 1998-11-16
JPH04230143A (ja) 1992-08-19
CA2042516A1 (en) 1991-11-16
AU7645591A (en) 1991-11-21
EP0456914A1 (en) 1991-11-21
DE69015165D1 (de) 1995-01-26
CA2042516C (en) 1996-05-21

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Owner name: ALCATEL N.V., A CORP OF NETHERLANDS, NETHERLANDS

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